Collecting charged particles, all having the same mass, from a multi-species plasma in which there are many charged particles having many different masses, involves the coordination and effective execution of several different tasks. First, of course, it is necessary to generate the multi-species plasma. This particular task can be accomplished in several ways, all of which are well known in the pertinent art. Second, once the multi-species plasma has been generated, it is then necessary to subject the multi-species plasma to physical phenomenon which will cause them to separate in a predictable manner according to their respective masses. Third, in a task that is somewhat related to the second task of separating the charged particles, all charged particles of a particular mass must be directed toward an area where they can be collected. Preferably, this is done while excluding particles of different masses which are directed elsewhere. Finally, the charged particles (ions) are collected.
In general, the physical phenomenon which are employed to separate the charged particles of a multi-species plasma from each other, involve techniques which will cause forces to be exerted on the particles. Importantly, these forces need to be proportional to the mass of the ion. One such technique involves the use of a plasma centrifuge. For example, Krishnan, M.: Centrifugal Isotope Separation in Zirconium Plasmas; Phys. Fluids 26 (9); pages 2676-2681; September, 1983, describes the use of centrifugal forces for the separation of charged particles (ions). Another technique which can be used to separate charged particles is disclosed in U.S. application Ser. No. 192,945, which was filed by Ohkawa on Nov. 16, 1998, for an invention entitled "Plasma Mass Filter" and which is assigned to the same assignee as the present invention. Unlike the plasma centrifuge techniques, the plasma filter disclosed by Ohkawa relies on the creation of an electromagnetic barrier which can be crossed by only particles having a mass that is greater than a predetermined value.
Heretofore, using plasma centrifuge techniques or plasma filter techniques as mentioned above, for many applications it has been possible to effectively separate high-mass particles from low-mass particles with a two-way split. There are, however, applications which can be envisioned wherein it would be desirable to achieve a more refined separation, such as with a three-way split into high-mass particles, intermediate-mass particles and low-mass particles.
In light of the above it is an object of the present invention to provide a mass segregator which is able to effectively isolate and separate a multi-species plasma into groups of high-mass particles, intermediate mass particles, and low-mass particles. It is another object of the present invention to provide a mass segregator which is able to effectively integrate the functional attributes of a plasma centrifuge with the functional attributes of a plasma mass filter to achieve effective separation of charged particles in a multi-species plasma according to their mass. Still another object of the present invention is to provide a mass segregator which can specifically isolate charged particles of a multi-species plasma that have masses greater than a predetermined value, while simultaneously separating charged particles of lesser mass from each other according to their respective masses. Yet another object of the present invention is to provide a mass segregator which is industrially easy to manufacture, relatively easy to use, and comparatively cost effective.